The majority of present day residential window units use lengths of extruded materials such as, for example, polyvinyl chloride (PVC) as framing for both the outer frame of the window unit as well as for the frame of the window sash. This is advantageous over classic wooden windows in that the extruded materials are cheaper to manufacture and are lighter and more durable than wood. There have been efforts to enhance the visual appeal of such extrusion-based windows as seen from the inside of a house to which the windows are fixed.
A number of solutions have been proposed to provide interior wood cladding to extrusion-based window units. In these cases, wood cladding parts are secured to the frame of the window unit to mask the extruded material of which the frame is made; separate wood cladding parts are secured to the sash of the window unit to mask the extruded material of which the sash is made.
Specific problems exist in relation to the sash of such window units. In existing window cladding systems, there is often a wood cladding part secured to the sash to act as a stop that secures a windowpane in the sash. Alternatively, there can be a wood cladding part secured to a glazing bead, usually made of an extruded material, which retains the windowpane in the sash.
One of the problems associated with such window cladding systems is that, for example, for casement and awning type window units, the wood parts secured to the sash become exposed to exterior weather conditions upon the window being open. Further, in cold weather conditions, the wood parts secured to the sash are subject to condensation trickling down the windowpane when high humidity levels are present inside the house. This is disadvantageous for a number of reasons. Firstly, exposure of parts of the window cladding system to exterior weather conditions and/or condensation can accelerate aging of those parts and therefore cause a color mismatch with parts of the window cladding system that are not exposed to the outside. Secondly, replacement of the windowpane, usually years after the window unit has been originally installed, requires the replacement of the window cladding part used to secure the windowpane to the sash. The odds of finding replacement window cladding parts that match the original cladding in color and grain are very low. Therefore, the replacement of a windowpane, and of its related wood cladding, is almost certain to skew the interior appearance of the window unit.
Another problem with existing extruded window systems having interior wood cladding is that either the frame of the window, the perimeter of the sash, or both, require special profiling to inter-fit with the window cladding parts. This implies that a manufacturer of windows must have an assembly/extrusion line dedicated to these interiorly clad windows. If the manufacturer also wishes to sell lower-end windows that do not have the wood cladding option, another assembly/extrusion line is required. An additional problem with existing window systems to which interior cladding can be installed is that they usually require adapter parts to be mounted on the window unit before the cladding itself can be installed. This means that the manufacturer/installer must carry these adapter parts in inventory. Yet another problem is that existing interior cladding assemblies for windows fail to conceal completely the frame of the window, the perimeter of the sash, and the glazing bead retaining the windowpane.
Therefore, it is desirable to provide a wooden window cladding assembly that covers or masks the interior side of a window unit made of extruded materials without exposing any part of the cladding assembly to exterior weather conditions upon the window being open. Further, it is desirable to provide a wooden window cladding assembly that can be retrofitted to the interior side of a window unit without requiring any special mating features on either the window unit or the cladding assembly.